GLP-1 analogues for type 2 diabetes
Glucagon-like peptide-1 (GLP-1) analogues are a relatively new group of medicines that can be prescribed for treating type 2 diabetes. These medicines are given as injections under the skin (this is called a subcutaneous injection).
- exenatide (Byetta) – twice daily dosing
- exenatide (Bydureon) – once weekly dosing
- liraglutide (Victoza) – once daily dosing. Note that liraglutide is not subsidised under the Pharmaceutical Benefits Scheme (PBS)
- lixisenatide – once daily dosing. Lixisenatide is not subsidised under the PBS.
GLP-1 analogues are available as pre-filled disposable injector pens. A health professional can demonstrate how to use these pens. GLP-1 analogues are injected before a meal, and should not be used after a meal.
Note about medicine names
Most medicines have two names: the active ingredient and the brand name. The active ingredient is the chemical in the medicine that makes it work. The brand name is the name given to the medicine by its manufacturer. There may be several brands that contain the same active ingredient. This website uses active ingredient names, with brand names in brackets. We also discuss medicines in groups or ‘classes’, when their effects or actions are very similar.
Many people think that because a medicine is new, it must be better than older medicines for the same condition – but this is not always the case. Read how to work out whether a new medicine is the best option for you.
If you are diagnosed with type 2 diabetes, your doctor may prescribe a medicine called metformin (or sometimes one of a group of medicines called sulfonylureas) to help control your blood glucose levels. Over time, taking a single medicine may not be enough to keep these glucose levels in the normal range.
Many people will start taking metformin and a sulfonylurea together when blood glucose cannot be controlled with a single medicine alone. However, some people can’t take this combination of medicines because they experience bad side effects, or they have a medical condition or another reason that prevents them from taking metformin or a sulfonylurea (ie, a contraindication). These people may have another kind of diabetes medicine added to their metformin (or sulfonylurea) instead.
GLP-1 analogues are one kind of diabetes medicine that can be used when this happens.
What do GLP-1 analogues do?
GLP-1 analogues reduce the level of glucose in the blood by increasing the amount of insulin in the blood, reducing the amount of glucose produced by the liver, and helping the stomach to empty more slowly so that glucose is absorbed more slowly.1
What are the benefits of taking a GLP-1 analogue?
GLP-1 analogues lower levels of glucose in the blood.
In clinical trials, some people with diabetes who received a GLP-1 analogue also experienced weight loss.1 It is important to remember that because GLP-1 analogues are a new group of medicines, their long-term benefits, including effects on weight, are not fully known.1
It is also not known if GLP-1 analogues reduce the risk of developing complications of diabetes such as heart disease or stroke. This will only become clearer when GLP-1 analogues are used by more people for longer periods of time.
Who can take a GLP-1 analogue?
GLP-1 analogues can be prescribed for people who have type 2 diabetes if healthy eating and exercise alone are insufficient to keep their blood glucose levels under control, and for people with type 2 diabetes who cannot take metformin or a sulfonylurea. People with type 2 diabetes whose blood glucose levels are not well controlled on the combination of metformin and a sulfonylurea or the combination of metformin and insulin may also be prescribed a GLP-1 analogue.
Note: Certain conditions apply before you can be prescribed a GLP-1 analogue on the PBS. At the time of publishing, this medicine can only be prescribed on the PBS for people with type 2 diabetes who:
- cannot tolerate the combination of metformin and a sulfonylurea
- do not meet their blood glucose targets on a combination of metformin and a sulfonylurea
- do not meet their blood glucose targets on a combination of metformin and insulin.
GLP-1 analogues may not be suitable for everyone – in particular, they may not be suitable for people with severe kidney problems or severe stomach or digestive problems.1
What are the side effects of GLP-1 analogues?
Common side effects include:
- nausea and/or vomiting - some people might need to stop taking exenatide or liraglutide because the nausea is so bad, but for most, the nausea settles down within a week or two and they can continue using the medication
- diarrhoea or constipation
- acid reflux
- hypoglycaemia (low blood glucose) when used together with a sulfonylurea or insulin.1
Less frequent side effects include allergic reactions, pancreatitis (swelling of the pancreas) and kidney problems.
GLP-1 analogues are usually started at a small dose and then gradually increased in dose to help reduce possible stomach and bowel side effects. For example, exenatide treatment is usually started as a small dose (for example, one 5 microgram injection twice a day), and then the dose can be increased after a few weeks to one 10 microgram injection twice a day. This gradual increase in dose can help to reduce possible stomach and bowel side effects.
Because GLP-1 analogues are relatively new medicines, not all of their side effects are known. This will only become clear when they have been used by more people for longer periods of time.
Who can I ask about side effects?
If you are concerned that you may have had side effects related to a medicine, seek medical advice or call the Adverse Medicines Events (AME) line on 1300 134 237 from anywhere in Australia (Mon–Fri, 9am–5pm) to report and discuss possible side effects.
It is important to tell your health professional about all the medicines you are taking — including prescription, over-the-counter and complementary medicines (herbal, ‘natural’, vitamins and minerals) — as they may interact with diabetes medicines and affect your blood glucose levels. This may mean that your doctor will need to adjust the dose or timing of your GLP-1 analogue, or make changes to your other medicines.
GLP-1 analogues are relatively new medicines so not all the potential interactions with other medicines are known.
Some non-diabetes medicines are known to affect blood glucose levels and can affect the way GLP-1 analogues work (interactions). Click on the following links to view tables that list some of these medicines:
In particular, exenatide slows down digestion and this may result in getting less of other medicines taken by mouth at the same time. It is reasonable to take other medicines such as antibiotics, at least 1 hour before, or 4 hours after an exenatide injection (when given twice daily).1
For more information, read the NPS Medicine Update article on exenatide.
Phone for medicines information
Call Medicines Line on 1300 MEDICINE (1300 633 424) to get information about your prescription, over-the-counter and complementary medicines (herbal, 'natural', vitamins and mineral supplements) from a pharmacist. Your call will be answered by healthdirect Australia (except Queensland and Victoria).
- Australian Medicines Handbook. Australian Medicines Handbook. Adelaide: Australian Medicines Handbook Pty Ltd: 2015. [Online] (accessed 28 May 2016).